Conventionally used for an inkjet printer that prints a desired image on paper serving as a printed medium has been an ink cartridge for an inkjet recorder (hereinafter simply referred to as an “ink cartridge”) that stores an ink container having an ink derivation section and an ink storage section for ink supply to an ink head.
There have been demands on such an ink cartridge for achieving easier performance of attachment to and detachment from the inkjet printer, having tolerance to, for example, fall during transport and handling processes and vibration upon transport, and achieving fabrication at low costs. Thus, to meet the demands described above, the applicants of the present invention have provided an ink cartridge as disclosed in Patent Literature 1 below.
As illustrated in FIG. 6A, a conventional ink cartridge 200 is a long and thin casing of a rectangular parallelepiped shape attached to and detached from a printer in a horizontal direction (in a direction of attachment and detachment operation). The ink cartridge 200 includes: a liquid storage container 210 formed of a thermoplastic film material filled with ink; an engagement surface 220 of resin or metal which is provided at one longitudinal end of the liquid storage container and which is engaged with a cartridge attaching mechanism of the printer; and an outer package 230 of a paper (a cardboard) as an outer box in which the liquid storage container 210 is inserted.
As illustrated in FIG. 6B, arranged at a substantial center of the engagement surface 220 is an ink supply port 240, which functions as an attachment and detachment mechanism fitted in a holder part 310 of a cartridge attaching mechanism 300 on a printer side. The fitting of the ink supply port 240 in the holder part 310 connects the ink cartridge 200 and the printer to each other, so that the ink is supplied from the ink cartridge 200 to the printer.
The ink supply port 240 is provided with a joint part 241 that is fitted in the holder part 310. The joint part 241 has a hollow-shaped inside, in which an inner plug 242 for sealing the ink supply port 240 is biased by a biasing force of a biasing unit in an ink outflow direction (a rightward direction in the figure and a direction equal to a direction in which the ink is loaded onto the printer). That is, it is structured such that an enlarged-diameter portion of a tip of the inner plug 242 is pushed towards an inside of an opening part of the supply port to thereby seal the ink supply port 240.
An insertion shaft 311 which pushes the inner plug 242 into the inside of the joint part 241 upon the engagement of the joint part 241 is projected from the holder part 310 with which the ink supply port 240 is engaged. Then upon loading of the ink cartridge 200 to the printer, the insertion shaft 311 pushes in the inner plug 242 to open the ink supply port 240 and achieves communication with an ink route 320 provided at the cartridge attaching mechanism 300, so that the ink in the container flows into the printer.